In the industrial field and in related fields of application, such as travel surveillance and medical technology, there exists a plurality of different applications of digital cameras, which mostly differ with respect to the requirements concerning the cameras. For instance, predominantly in the field of travel surveillance cameras, there is need for a high horizontal resolution, which facilitates the reading of license plates on a respective number of travel lanes. In the automatic inspection of, e.g., brake disks, on the other hand, a different resolution is required, which facilitates the inspection of specific check gauges with a pre-determined precision.
FIG. 1 shows schematically and exemplarily the structure of a digital camera 10 with a lens 22. A scene 30 is projected via the lens 22 onto an image sensor 31, which comprises a regular arrangement of light-sensitive elements, so-called pixels. The image sensor 31 conveys electronic data to a processing unit 32, which usually is located in the camera 10 and which, e.g., comprises a processor, a digital signal processor (DSP), or a so-called field programmable gate array (FPGA). It can thereby be necessary to convert analog image data into digital image data, e.g., by means of an analog-to-digital converter (not shown in the figure). Where applicable, further desired mathematical operations, e.g., a color correction or a conversion into another image format, are executed on the image data in the processing unit 32 before the data are subsequently output as an electronic signal 34 via an interface 33.
The above-mentioned different requirements concerning digital cameras are usually addressed by the camera manufacturers with a large number of different camera models. Providing such a large number of camera variants requires a high organizational and financial effort, e.g., in the development, the production, the marketing, the distribution, and the logistic. It would, therefore, be desirable to be able to reduce the variety of camera variants or of the hard and software modules from which they are assembled.
If one has a closer look at the formation of the variants of digital cameras, it can be seen that, in particular, the large number of the different required types of image sensors inflates the variety of the variants. It would, therefore, be desirable to be able to fulfill the different requirements concerning digital cameras with fewer types of image sensors. Particularly important distinguishing features in this context are the size and the number of pixels of an image sensor, wherein the physical size of the sensor or of its diagonal, respectively, results from these characteristics as further important distinguishing features.
Starting from the above-described situation regarding the variety of digital camera variants, the present inventor has considered it an object to develop a means to generate, from an image of an image sensor with a first pixel size, an image with a second pixel size, which preferably is freely selectable and differs from the first pixel size, without the need of using a different image sensor type with the second pixel size. In this way, more than one application with more than one requirement concerning the pixel size and number could be addressed with the same camera hardware with the same image sensor type. This may allow to save at least part of the costs for the forming of the different variants and/or to reduce the respective organizational effort.